(CNN) -- A terrorist group led by Abu Musab al-Zarqawi said Tuesday it abducted a member of Japan's armed forces and threatened to behead him if the Japanese government does not withdraw its troops from Iraq within two days.

The video shows the hostage kneeling in front of three masked militants dressed in black. The one in the middle reads a statement from the group, while the other two brandish weapons.

"We grant the Japanese government 48 hours to withdraw its troops from Iraq or this infidel will be beheaded," the statement says.

At one point, the hostage looks down and one of the militants grabs him by his hair and forces him to look up at the camera. The militants identify the man as a member of Japan's armed forces, though he does not appear to be in uniform.

The videotaped message was posted on an Islamist Web site that has been used by al-Zarqawi's group in the past.

The Japanese government had no immediate comment.

The group that issued the statement called itself the Qaeda of Jihad, a name al-Zarqawi's group has given itself after a recent pledge of loyalty to Osama bin Laden. His group had previously been known as Unification and Jihad.

Japan has about 550 troops in Iraq.

Rising threat

Insurgents warned on Tuesday that any U.S.-led offensive in Falluja would lead to attacks on Iraqi and coalition troops with "weapons and military tactics they have not experienced before."

On an APTN video monitored by CNN, a masked gunman read a statement promising a counterpunch against U.S., Iraqi and multinational targets throughout Iraq "in the ways and forms of our choosing."

U.S. warplanes have regularly been pounding sites connected to al-Zarqawi's terrorist network for many weeks, and the Iraqi interim government has warned of the possibility of an all-out offensive to oust militants from Falluja, where insurgents are firmly entrenched.

Standing in front of a banner that said "The Movement of Iraqi National Resistance Regiments" along with seven other masked and armed men, the speaker delivered words on behalf of the "factions of the Islamic Resistance Movement in Iraq."

"We swear in the name of God that all armed factions will attack all military and civilian targets of the occupation forces and the interim government" if there is an offensive, he said.

The speaker said the Iraqi military and government employees will be targets if they don't quit their jobs.

The interim government was also accused of "aborting a peaceful solution with the people of Falluja."

Government officials and Falluja leaders have been discussing ways to bring peace to the city and oust the insurgency. Government leaders have threatened an offensive if the local leaders don't hand over al-Zarqawi and other militants.

At least two of the armed people in the video were clad in Iraqi military uniforms from the Saddam Hussein era.

Earlier Tuesday, the U.S. military said a morning airstrike had killed a "known associate" of al-Zarqawi's in Falluja.

"Multiple sources reported that a known associate of the Zarqawi network was present at the time of the strike," the U.S. military said in a statement.

However, a Falluja resident strongly disagreed.

"These four houses that were destroyed were empty. The families left them about a month ago," he said. "There is no one there, no Zarqawi, no militants, no mujahedeen. The plane hit [the houses] at exactly 0300 local time. Thank God there was no one there."

Al-Zarqawi said in an audiotape posted on a Web site that he was behind the bombing of the U.N. headquarters in Baghdad on August 19, 2003, that killed 22 civilians, including the U.N.'s chief envoy to Iraq, Sergio Vieira de Mello

A group linked to al-Zarqawi -- Unification and Jihad -- has said it has killed numerous Westerners in Iraq, including two Americans and a Briton kidnapped in September and who were later beheaded.

'Major negligence'

Iraqi interim Prime Minister Ayad Allawi said Tuesday that Saturday's massacre of 44 Iraqi national guard soldiers resulted from "major negligence on the part of some members of the multinational forces."

Speaking to the country's National Council, Allawi did not elaborate on his claim, but said a committee will be investigating the "vicious" act "where a large number of national guards met martyrdom."

Al-Zarqawi's terrorist network claimed responsibility for the execution-style massacre of the 44 soldiers and four drivers east of Baghdad.

U.S. officials said insurgents set up a false checkpoint where they ambushed the Iraqi soldiers as they were returning home after graduating from training camp, U.S. officials said. The bodies -- each shot in the head -- were found several hours later, about midnight, near the Iranian border, Iraqi officials said.

Deadly attacks in Baghdad, Baquba

At least five people died Tuesday during fighting in the cities of Baquba and Baghdad, including a mother and daughter who were caught in a crossfire, a police officer, a local council official, and his driver.

The mother and daughter were killed in the Baghdad neighborhood of al-Shaljiya -- caught in crossfire between U.S. military and insurgents, authorities said. Seven other people -- including two children -- were injured in the clash, Al-Karkh Hospital officials said.

In Baquba, a Diyala provincial council member and his driver were found shot to death Tuesday morning in a car, U.S. military sources told CNN.

The official, Neaima Hassan Neaima, and his driver were found in southern Baquba where insurgents had targeted Iraqi police with two roadside bombs earlier in the day.

In the first attack, a police officer was killed and three others were wounded when a bomb detonated near a police patrol at Muwaffaq traffic circle. Nearby and soon after, another bomb detonated, wounding three police officers who were responding to the first explosion.

Another council member -- Sheikh Dhari al-Dulaimi, chairman of the council in the town of Mahmoudiya -- was shot to death Monday, police said.

Baghdad police sources told CNN that insurgents ambushed him as he was driving alone in his car. Mahmoudiya is about 20 miles south of Baghdad.

Police also said insurgents shot and seriously wounded the imam of Mahmoudiya's Grand Mosque, Sheikh Mustafa al-Mudhafar on Monday. He was rushed to al-Yarmouk hospital in Baghdad.

Explosives not found

The Bush campaign said an NBC News report Monday evening that powerful explosives -- enough to detonate a nuclear weapon -- that were supposed to be housed at the al-Qaqaa facility south of Baghdad could not be found when invading U.S. troops arrived at the site.

Campaign spokesman Steve Schmidt said the report showed Kerry's accusations that the disappearance of the explosives indicated a failure on the president's part were "baseless."

However, NBC reporter Lai Ling Jew told the network's cable arm, MSNBC, that the 24-hour visit by elements of the 101st Airborne Division was "more of a pit stop." U.S. troops did not conduct a detailed search of the compound, she said.

"Certainly, some of the soldiers headed off on their own [and] looked through the bunkers just to look at the vast amount of ordnance lying around. But as far as we could tell, there was no move to secure the weapons, nothing to keep looters away."

Other developments

A top adviser to the Saudi royal family dimissed suggestions that money from the kingdom was funding Iraq's insurgents and called reports that his government has not done enough to stop such payments "irresponsible." Adel al-Jubeir, chief foreign policy adviser to Crown Prince Adbullah, said the Saudi government had taken "very strong steps" and that reports, like those from Florida Sen. Bob Graham, indicating Saudi Arabia was attempting to undermine U.S. interests, were not "supported by the facts." The Defense Intelligence Agency recently reported insurgents recieved funding from external donors, including sympathetic Saudis.

U.S. Marines have paid about $1.9 million in the past month in compensation to roughly 2,660 Iraqis in Najaf who lost property or loved ones in fighting there, the 11th Marine Expeditionary Unit said in a statement Monday. Fighting in August between U.S. and Iraqi forces and militia loyal to rebel cleric Muqtada al-Sadr left many Iraqis dead before a peace deal was reached. "Condolence payments," the statement said, "are being paid to express sympathy to those injured or who lost a family member during the fighting. Collateral damage repair payments are intended for Iraqis who experienced damage to their home, business or other property."

The American Foreign Service Association, a union representing U.S. foreign service workers, called Monday for increased security in Iraq after the deadly attack Sunday on a U.S. State Department security official. Ed Seitz, who was assigned to the U.S. Embassy in Baghdad, was killed in a mortar attack on a U.S. Army base near the capital's airport.